[Pkg-mailman-hackers] Bug#997019: Bug#997019: The issue is IPv6 related

[Andrew Hodgson]

Colin Turner wrote:

>There are no firewall rules that seem to be relevant, so I guess mailman3 is not reachable on IPv6 maybe but I haven’t investigated further.

The LMTP runner listens on 127.0.0.1:8024 by default however this can be changed in the mailman.cfg

https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/config/docs/config.html

However, I think the issue you ran into was Exim specific and not related to Mailman LMTP runner listening on ::1. I had a similar issue when upgrading to Bullseye and on the old host Mailman LMTP runner was still only listening on 127.0.0.1:8024. Based on this doc:

https://www.exim.org/exim-html-current/doc/html/spec_html/ch-the_dnslookup_router.html

I made a slightly different edit to the transport: 

mailman_transport:
  debug_print = "Email for mailman"
  driver = smtp
  protocol = lmtp
  allow_localhost
  gethostbyname
  hosts = localhost
  port = 8024
  rcpt_include_affixes = true

I never tried to make Mailman LMTP listen on IPV6.

Thanks.
Andrew.